This invention relates, on the one hand, to a process for charging an electrochemical generator consisting of a plurality of cells, which are electrically in series, comprising a zinc negative electrode and a positive electrode between which a basic electrolyte containing solubilized zinc circulates from one cell to the next and, on the other hand, this electrochemical generator for putting said process into practice, the electrolyte being made turbulent near the negative electrode.
So far, attempts to reliably achieve a suitable zinc deposit on the zinc negative electrode during cycling of reversible batteries having a basic electrolyte using this metal have been unsuccessful. The nickel zinc battery is the best known example of such batteries. During charging of these batteries, the zinc deposit gives rise either to the formation of foams and dendrites or to irregular bulges which quickly cause short circuits between the electrodes. Until now, these defects have not made it possible to take advantage of the great specific energy of electrochemical couples using zinc.
The electrolyte is made to circulate to improve the zinc deposit. The morphology of the zinc deposit is more suitable, the greater is the speed of the electrolyte during deposit.
It was disclosed in French Pat. No. 2 056 971 to charge batteries having a zinc negative electrode by a pulse-charging current. French Pat. No. 2 097 424 proposed a charging current exhibiting discharge (anode) pulses between charging pulses.